Krey Karol L, Nabity Paul D, Blubaugh Carmen K, Fu Zhen, Van Leuven James T, Reganold John P, Berim Anna, Gang David R, Jensen Andrew S, Snyder William E
Department of Entomology, Washington State University, Pullman, WA, United States.
Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States.
Front Sustain Food Syst. 2020 Jul;4. doi: 10.3389/fsufs.2020.00097. Epub 2020 Jul 17.
Plants deploy a variety of chemical and physical defenses to protect themselves against herbivores and pathogens. Organic farming seeks to enhance these responses by improving soil quality, ultimately altering bottom up regulation of plant defenses. While laboratory studies suggest this approach is effective, it remains unclear whether organic agriculture encourages more-active plant defenses under real-world conditions. Working on the farms of cooperating growers, we examined gene expression in the leaves of two potato () varieties, grown on organic vs. conventional farms. For one variety, , we found significantly heightened initiation of genes associated with plant-defense pathways in plants grown in organic vs. conventional fields. Organic fields exhibited lower levels of nitrate in soil and of nitrogen in plant foliage, alongside differences in communities of soil bacteria, suggesting possible links between soil management and observed differences in plant defenses. Additionally, numbers of predatory and phloem-feeding insects were higher in organic than conventional fields. A second potato variety, , which is generally grown using fewer inputs and in poorer-quality soils, exhibited lower overall herbivore and predator numbers, few differences in soil ecology, and no differences in gene-activity in organic and conventional farming systems. Altogether, our results suggest that organic farming has the potential to increase plants' resistance to herbivores, possibly facilitating reduced need for insecticide applications. These benefits appear to be mediated by plant variety and/or farming context.
植物会采用多种化学和物理防御手段来保护自身免受食草动物和病原体的侵害。有机农业旨在通过改善土壤质量来增强这些防御反应，最终改变植物防御的自下而上的调节机制。虽然实验室研究表明这种方法是有效的，但在现实世界条件下，有机农业是否能促进植物更积极的防御仍不清楚。我们在合作种植者的农场开展研究，检测了在有机农场和传统农场种植的两个马铃薯（）品种叶片中的基因表达情况。对于其中一个品种，我们发现与种植在有机农田和传统农田中的植物防御途径相关的基因启动显著增强。有机农田土壤中的硝酸盐含量和植物叶片中的氮含量较低，同时土壤细菌群落也存在差异，这表明土壤管理与观察到的植物防御差异之间可能存在联系。此外，有机农田中捕食性昆虫和取食韧皮部的昆虫数量比传统农田中的更多。第二个马铃薯品种，通常种植投入较少且土壤质量较差，其总体食草动物和捕食者数量较少，土壤生态差异不大，在有机和传统种植系统中的基因活性也没有差异。总体而言，我们的结果表明有机农业有可能增强植物对食草动物的抗性，可能有助于减少杀虫剂的使用需求。这些益处似乎由植物品种和/或种植环境介导。
